/*******************************************************************
  NOTE:
  The early netatalk 2.x was based on UCS-2.
  UCS-2 don't support chars above U+10000.
  Recent netatalk is based on UTF-16.
  UTF-16 can support chars above U+10000, using Surrogate Pair.
  However, Surrogate Pair is complex, dirty, filthy and disagreeable.
  There might still be latent bugs...
********************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <atalk/logger.h>
#include <errno.h>
#include <arpa/inet.h>

#include <atalk/unicode.h>
#include <atalk/byteorder.h>

#include "precompose.h"

/*******************************************************************
 Convert a string to lower case.
 return True if any char is converted
********************************************************************/
/* surrogate pair support */

int strlower_w(ucs2_t *s)
{
	int ret = 0;

	while (*s) {
		if ((0xD800 <= *s) && (*s < 0xDC00)) {
			if ((0xDC00 <= s[1]) && (s[1] < 0xE000)) {
				uint32_t s_sp = (uint32_t)*s << 16 | (uint32_t)s[1];
				uint32_t v_sp = tolower_sp(s_sp);
				if (v_sp != s_sp) {
					*s = v_sp >> 16;
					s++;
					*s = v_sp & 0xFFFF;
					ret = 1;
				}
			}
		} else {
			ucs2_t v = tolower_w(*s);
			if (v != *s) {
				*s = v;
				ret = 1;
			}
		}
		s++;
	}
	return ret;
}

/*******************************************************************
 Convert a string to upper case.
 return True if any char is converted
********************************************************************/
/* surrogate pair support */

int strupper_w(ucs2_t *s)
{
	int ret = 0;

	while (*s) {
		if ((0xD800 <= *s) && (*s < 0xDC00)) {
			if ((0xDC00 <= s[1]) && (s[1] < 0xE000)) {
				uint32_t s_sp = (uint32_t)*s << 16 | (uint32_t)s[1];
				uint32_t v_sp = toupper_sp(s_sp);
				if (v_sp != s_sp) {
					*s = v_sp >> 16;
					s++;
					*s = v_sp & 0xFFFF;
					ret = 1;
				}
			}
		} else {
			ucs2_t v = toupper_w(*s);
			if (v != *s) {
				*s = v;
				ret = 1;
			}
		}
		s++;
	}
	return ret;
}

/*******************************************************************
wide & sp islower()
determine if a character is lowercase
********************************************************************/
/* These functions are not used. */

int islower_w(ucs2_t c)
{
	return ( c == tolower_w(c));
}

int islower_sp(uint32_t c_sp)
{
	return ( c_sp == tolower_sp(c_sp));
}

/*******************************************************************
wide & sp isupper()
determine if a character is uppercase
********************************************************************/
/* These functions are not used. */

int isupper_w(ucs2_t c)
{
	return ( c == toupper_w(c));
}

int isupper_sp(uint32_t c_sp)
{
	return ( c_sp == toupper_sp(c_sp));
}

/*******************************************************************
wide strlen()
 Count the number of characters in a UTF-16 string.
********************************************************************/
/* NOTE: one surrogate pair is two characters. */

size_t strlen_w(const ucs2_t *src)
{
	size_t len;

	for(len = 0; *src++; len++) ;

	return len;
}

/*******************************************************************
wide strnlen()
 Count up to max number of characters in a UTF-16 string.
********************************************************************/
/* NOTE: one surrogate pair is two characters. */

size_t strnlen_w(const ucs2_t *src, size_t max)
{
	size_t len;

	for(len = 0; *src++ && (len < max); len++) ;

	return len;
}

/*******************************************************************
wide strchr()
********************************************************************/
/* NOTE: hi and lo of surrogate pair are separately processed. */

ucs2_t *strchr_w(const ucs2_t *s, ucs2_t c)
{
	while (*s != 0) {
		if (c == *s) return (ucs2_t *)s;
		s++;
	}
	if (c == *s) return (ucs2_t *)s;

	return NULL;
}

/*******************************************************************
wide & sp strcasechr()
********************************************************************/
/* NOTE: separately process BMP and surrogate pair */

ucs2_t *strcasechr_w(const ucs2_t *s, ucs2_t c)
{
	while (*s != 0) {
		if (tolower_w(c) == tolower_w(*s)) return (ucs2_t *)s;
		s++;
	}
	if (c == *s) return (ucs2_t *)s;

	return NULL;
}

ucs2_t *strcasechr_sp(const ucs2_t *s, uint32_t c_sp)
{
	if (*s == 0) return NULL;
	while (s[1] != 0) {
		if (tolower_sp(c_sp) == tolower_sp((uint32_t)*s << 16 | (uint32_t)s[1])) return (ucs2_t *)s;
		s++;
	}

	return NULL;
}

/*******************************************************************
wide strcmp()
********************************************************************/
/* no problem of surrogate pair */

int strcmp_w(const ucs2_t *a, const ucs2_t *b)
{
	while (*b && *a == *b) { a++; b++; }
	return (*a - *b);
	/* warning: if *a != *b and both are not 0 we retrun a random
	   greater or lesser than 0 number not realted to which
	   string is longer */
}

/*******************************************************************
wide strncmp()
********************************************************************/
/* no problem of surrogate pair */

int strncmp_w(const ucs2_t *a, const ucs2_t *b, size_t len)
{
	size_t n = 0;
	while ((n < len) && *b && *a == *b) { a++; b++; n++;}
	return (len - n)?(*a - *b):0;
}

/*******************************************************************
wide strstr()
********************************************************************/
/* no problem of surrogate pair */

ucs2_t *strstr_w(const ucs2_t *s, const ucs2_t *ins)
{
	ucs2_t *r;
	size_t slen, inslen;

	if (!s || !*s || !ins || !*ins) return NULL;
	slen = strlen_w(s);
	inslen = strlen_w(ins);
	r = (ucs2_t *)s;
	while ((r = strchr_w(r, *ins))) {
		if (strncmp_w(r, ins, inslen) == 0) return r;
		r++;
	}
	return NULL;
}

/*******************************************************************
wide strcasestr()
********************************************************************/
/* surrogate pair support */

ucs2_t *strcasestr_w(const ucs2_t *s, const ucs2_t *ins)
{
	ucs2_t *r;
	size_t slen, inslen;

	if (!s || !*s || !ins || !*ins) return NULL;
	slen = strlen_w(s);
	inslen = strlen_w(ins);
	r = (ucs2_t *)s;

	if ((0xD800 <= *ins) && (*ins < 0xDC00)) {
		if ((0xDC00 <= ins[1]) && (ins[1] < 0xE000)) {
			uint32_t ins_sp = (uint32_t)*ins << 16 | (uint32_t)ins[1];
			while ((r = strcasechr_sp(r, ins_sp))) {
				if (strncasecmp_w(r, ins, inslen) == 0) return r;
				r++;
			}
		} else {
			return NULL; /* illegal sequence */
		}
	} else {
		while ((r = strcasechr_w(r, *ins))) {
			if (strncasecmp_w(r, ins, inslen) == 0) return r;
			r++;
		}
	}
	return NULL;
}

/*******************************************************************
wide strcasecmp()
case insensitive string comparison
********************************************************************/
/* surrogate pair support */

int strcasecmp_w(const ucs2_t *a, const ucs2_t *b)
{
	int ret;

	while (*a && *b) {
		if ((0xD800 <= *a) && (*a < 0xDC00)) {
			if ((ret = tolower_sp((uint32_t)*a << 16 | (uint32_t)a[1]) - tolower_sp((uint32_t)*b << 16 | (uint32_t)b[1]))) return ret;
			a++;
			b++;
			if (!(*a && *b)) return (tolower_w(*a) - tolower_w(*b)); /* avoid buffer over run */
		} else {
			if ((ret = tolower_w(*a) - tolower_w(*b))) return ret;
		}
		a++;
		b++;
	}
	return (tolower_w(*a) - tolower_w(*b));
}

/*******************************************************************
wide strncasecmp()
case insensitive string comparison, length limited
********************************************************************/
/* NOTE: compare up to 'len+1' if 'len' isolate surrogate pair  */

int strncasecmp_w(const ucs2_t *a, const ucs2_t *b, size_t len)
{
	size_t n = 0;
	int ret;

	while ((n < len) && *a && *b) {
		if ((0xD800 <= *a) && (*a < 0xDC00)) {
			if ((ret = tolower_sp((uint32_t)*a << 16 | (uint32_t)a[1]) - tolower_sp((uint32_t)*b << 16 | (uint32_t)b[1]))) return ret;
			a++;
			b++;
			n++;
			if (!((n < len) && *a && *b)) return (tolower_w(*a) - tolower_w(*b));
		} else {
			if ((ret = tolower_w(*a) - tolower_w(*b))) return ret;
		}
		a++;
		b++;
		n++;
	}
	return (len - n)?(tolower_w(*a) - tolower_w(*b)):0;
}

/*******************************************************************
wide strndup()
duplicate string
********************************************************************/
/* NOTE: not check isolation of surrogate pair */
/* if len == 0 then duplicate the whole string */

ucs2_t *strndup_w(const ucs2_t *src, size_t len)
{
	ucs2_t *dest;

	if (!len) len = strlen_w(src);
	dest = (ucs2_t *)malloc((len + 1) * sizeof(ucs2_t));
	if (!dest) {
		LOG (log_error, logtype_default, "strdup_w: out of memory!");
		return NULL;
	}

	memcpy(dest, src, len * sizeof(ucs2_t));
	dest[len] = 0;

	return dest;
}

/*******************************************************************
wide strdup()
duplicate string
********************************************************************/
/* no problem of surrogate pair */

ucs2_t *strdup_w(const ucs2_t *src)
{
	return strndup_w(src, 0);
}

/*******************************************************************
copy a string with max len
********************************************************************/
/* This function is not used. */
/* NOTE: not check isolation of surrogate pair */

ucs2_t *strncpy_w(ucs2_t *dest, const ucs2_t *src, const size_t max)
{
	size_t len;

	if (!dest || !src) return NULL;

	for (len = 0; (src[len] != 0) && (len < max); len++)
		dest[len] = src[len];
	while (len < max)
		dest[len++] = 0;

	return dest;
}


/*******************************************************************
append a string of len bytes and add a terminator
********************************************************************/
/* These functions are not used. */

/* NOTE: not check isolation of surrogate pair */
ucs2_t *strncat_w(ucs2_t *dest, const ucs2_t *src, const size_t max)
{
	size_t start;
	size_t len;

	if (!dest || !src) return NULL;

	start = strlen_w(dest);
	len = strnlen_w(src, max);

	memcpy(&dest[start], src, len*sizeof(ucs2_t));
	dest[start+len] = 0;

	return dest;
}

/* no problem of surrogate pair */
ucs2_t *strcat_w(ucs2_t *dest, const ucs2_t *src)
{
	size_t start;
	size_t len;

	if (!dest || !src) return NULL;

	start = strlen_w(dest);
	len = strlen_w(src);

	memcpy(&dest[start], src, len*sizeof(ucs2_t));
	dest[start+len] = 0;

	return dest;
}


/*******************************************************************
binary search for pre|decomposition
********************************************************************/

static ucs2_t do_precomposition(unsigned int base, unsigned int comb) 
{
	int min = 0;
	int max = PRECOMP_COUNT - 1;
	int mid;
	uint32_t sought = (base << 16) | comb, that;

	/* binary search */
	while (max >= min) {
		mid = (min + max) / 2;
		that = (precompositions[mid].base << 16) | (precompositions[mid].comb);
		if (that < sought) {
			min = mid + 1;
		} else if (that > sought) {
			max = mid - 1;
		} else {
			return precompositions[mid].replacement;
		}
	}
	/* no match */
	return 0;
}

/* ------------------------ */
static uint32_t do_precomposition_sp(unsigned int base_sp, unsigned int comb_sp) 
{
	int min = 0;
	int max = PRECOMP_SP_COUNT - 1;
	int mid;
	uint64_t sought_sp = ((uint64_t)base_sp << 32) | (uint64_t)comb_sp, that_sp;

	/* binary search */
	while (max >= min) {
		mid = (min + max) / 2;
		that_sp = ((uint64_t)precompositions_sp[mid].base_sp << 32) | ((uint64_t)precompositions_sp[mid].comb_sp);
		if (that_sp < sought_sp) {
			min = mid + 1;
		} else if (that_sp > sought_sp) {
			max = mid - 1;
		} else {
			return precompositions_sp[mid].replacement_sp;
		}
	}
	/* no match */
	return 0;
}

/* -------------------------- */
static uint32_t do_decomposition(ucs2_t base) 
{
	int min = 0;
	int max = DECOMP_COUNT - 1;
	int mid;
	uint32_t sought = base;
	uint32_t result, that;

	/* binary search */
	while (max >= min) {
		mid = (min + max) / 2;
		that = decompositions[mid].replacement;
		if (that < sought) {
			min = mid + 1;
		} else if (that > sought) {
			max = mid - 1;
		} else {
			result = (decompositions[mid].base << 16) | (decompositions[mid].comb);
			return result;
		}
	}
	/* no match */
	return 0;
}

/* -------------------------- */
static uint64_t do_decomposition_sp(unsigned int base_sp) 
{
	int min = 0;
	int max = DECOMP_SP_COUNT - 1;
	int mid;
	uint32_t sought_sp = base_sp;
	uint32_t that_sp;
	uint64_t result_sp;

	/* binary search */
	while (max >= min) {
		mid = (min + max) / 2;
		that_sp = decompositions_sp[mid].replacement_sp;
		if (that_sp < sought_sp) {
			min = mid + 1;
		} else if (that_sp > sought_sp) {
			max = mid - 1;
		} else {
			result_sp = ((uint64_t)decompositions_sp[mid].base_sp << 32) | ((uint64_t)decompositions_sp[mid].comb_sp);
			return result_sp;
		}
	}
	/* no match */
	return 0;
}

/*******************************************************************
pre|decomposition

   we can't use static, this stuff needs to be reentrant
   static char comp[MAXPATHLEN +1];

   We don't implement Singleton and Canonical Ordering.
   We ignore CompositionExclusions.txt.
   because they cause the problem of the roundtrip
   such as Dancing Icon.

   exclude U2000-U2FFF, UFE30-UFE4F and U2F800-U2FA1F ranges
   in precompose.h from composition according to AFP 3.x spec
********************************************************************/

size_t precompose_w (ucs2_t *name, size_t inplen, ucs2_t *comp, size_t *outlen)
{
	size_t i;
	ucs2_t base, comb;
	uint32_t base_sp, comb_sp;
	ucs2_t *in, *out;
	ucs2_t lindex, vindex;
	ucs2_t result;
	uint32_t result_sp;
	size_t o_len = *outlen;
	
	if (!inplen || (inplen & 1) || inplen > o_len)
		return (size_t)-1;
	
	i = 0;
	in  = name;
	out = comp;
	
	base = *in;
	while (*outlen > 2) {
		i += 2;
		if (i == inplen) {
			*out = base;
			out++;
			*out = 0;
			*outlen -= 2;
			return o_len - *outlen;
		}
		in++;
		comb = *in;
		result = 0;

		/* Non-Combination Character */
		if (comb < 0x300) ;
		
		/* Unicode Standard Annex #15 A10.3 Hangul Composition */
		/* Step 1 <L,V> */
		else if ((VBASE <= comb) && (comb <= VBASE + VCOUNT)) {
			if ((LBASE <= base) && (base < LBASE + LCOUNT)) {
				result = 1;
				lindex = base - LBASE;
				vindex = comb - VBASE;
				base = SBASE + (lindex * VCOUNT + vindex) * TCOUNT;
			}
		}
		
		/* Step 2 <LV,T> */
		else if ((TBASE < comb) && (comb < TBASE + TCOUNT)) {
			if ((SBASE <= base) && (base < SBASE + SCOUNT) && (((base - SBASE) % TCOUNT) == 0)) {
				result = 1;
				base += comb - TBASE;
			}
		}
		
		/* Binary Search for Surrogate Pair */
		else if ((0xD800 <= base) && (base < 0xDC00)) {
			if ((0xDC00 <= comb) && (comb < 0xE000) && (i + 6 <= inplen)) {
				base_sp = ((uint32_t)base << 16) | (uint32_t)comb;
				do {
					comb_sp = ((uint32_t)in[1] << 16) | (uint32_t)in[2];
					if ((result_sp = do_precomposition_sp(base_sp, comb_sp))) {
						base_sp = result_sp;
						i += 4;
						in +=2;
					}
				} while ((i + 6 <= inplen) && result_sp) ;

				*out = base_sp >> 16;
				out++;
				*outlen -= 2;

				if (*outlen <= 2) {
					errno = E2BIG;
					return (size_t)-1;
				}

				*out = base_sp & 0xFFFF;
				out++;
				*outlen -= 2;

				i += 2;
				if (i == inplen) {
					out++;
					*out = 0;
					return o_len - *outlen;
				}
				in++;
				base = *in;

				result = 1;
			}
		}

		/* Binary Search for BMP */
		else if ((result = do_precomposition(base, comb))) {
			base = result;
		}
		
		if (!result) {
			*out = base;
			out++;
			*outlen -= 2;
			base = comb;
		}
	}

	errno = E2BIG;
	return (size_t)-1;
}

/* --------------- */
size_t decompose_w (ucs2_t *name, size_t inplen, ucs2_t *comp, size_t *outlen)
{
	size_t i;
	size_t comblen;
	ucs2_t base, comb[COMBBUFLEN];
	uint32_t base_sp;
	ucs2_t sindex, tjamo;
	ucs2_t *in, *out;
	unsigned int result;
	uint64_t result_sp;
	size_t o_len = *outlen;

	if (!inplen || (inplen & 1))
		return (size_t)-1;
	i = 0;
	in  = name;
	out = comp;

	while (i < inplen) {
		base = *in;
		comblen = 0;
		
		/* check ASCII first. this is frequent. */
		if (base <= 0x007f) ;
		
		/* Unicode Standard Annex #15 A10.2 Hangul Decomposition */
		else if ((SBASE <= base) && (base < SBASE + SCOUNT)) {
			sindex = base - SBASE;
			base = LBASE + sindex / NCOUNT;
			comb[COMBBUFLEN-2] = VBASE + (sindex % NCOUNT) / TCOUNT;
			
			/* <L,V> */
			if ((tjamo = TBASE + sindex % TCOUNT) == TBASE) {
				comb[COMBBUFLEN-1] = comb[COMBBUFLEN-2];
				comblen = 1;
			}
			
			/* <L,V,T> */
			else {
				comb[COMBBUFLEN-1] = tjamo;
				comblen = 2;
			}
		}
		
		/* Binary Search for Surrogate Pair */
		else if ((0xD800 <= base) && (base < 0xDC00)) {
			if (i + 2 < inplen) {
				base_sp =  ((uint32_t)base << 16) | (uint32_t)in[1];
				do {
					if ( !(result_sp = do_decomposition_sp(base_sp))) break;
					comblen += 2;
					base_sp = result_sp >> 32;
					comb[COMBBUFLEN-comblen] = (result_sp >> 16) & 0xFFFF;  /* hi */
					comb[COMBBUFLEN-comblen+1] = result_sp & 0xFFFF;        /* lo */
				} while (comblen < MAXCOMBSPLEN);

				if (*outlen < (comblen + 1) << 1) {
					errno = E2BIG;
					return (size_t)-1;
				}

				*out = base_sp >> 16;   /* hi */
				out++;
				*outlen -= 2;
				
				base = base_sp & 0xFFFF; /* lo */
				
				i += 2;
				in++;
			}
		}
			
		/* Binary Search for BMP */
		else {
			do {
				if ( !(result = do_decomposition(base))) break;
				comblen++;
				base = result  >> 16;
				comb[COMBBUFLEN-comblen] = result & 0xFFFF;
			} while ((0x007f < base) && (comblen < MAXCOMBLEN));
		}
		
		if (*outlen < (comblen + 1) << 1) {
			errno = E2BIG;
			return (size_t)-1;
		}
		
		*out = base;
		out++;
		*outlen -= 2;
		
		while ( comblen > 0 ) {
			*out = comb[COMBBUFLEN-comblen];
			out++;
			*outlen -= 2;
			comblen--;
		}
		
		i += 2;
		in++;
	}
	
	*out = 0;
	return o_len-*outlen;
}

/*******************************************************************
length of UTF-8 character and string
********************************************************************/

size_t utf8_charlen ( char* utf8 )
{
	unsigned char *p;

	p = (unsigned char*) utf8;
	
	if ( *p < 0x80 )
		return (1);
	else if ( *p > 0xC1 && *p < 0xe0 && *(p+1) > 0x7f && *(p+1) < 0xC0)
		return (2);
	else if ( *p == 0xe0 && *(p+1) > 0x9f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0)
		return (3);
	else if ( *p > 0xe0  && *p < 0xf0 && *(p+1) > 0x7f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0)
		return (3);
	else if ( *p == 0xf0 && *(p+1) > 0x8f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
		return (4);
	else if ( *p > 0xf0 && *p < 0xf4 && *(p+1) > 0x7f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
		return (4);
	else if ( *p == 0xf4 && *(p+1) > 0x7f && *(p+1) < 0x90 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
		return (4);
	else
		return ((size_t) -1);
}


size_t utf8_strlen_validate ( char * utf8 )
{
	size_t len;
	unsigned char *p;

	p = (unsigned char*) utf8;
	len = 0;

	/* see http://www.unicode.org/unicode/reports/tr27/ for an explanation */

	while ( *p != '\0')
	{
		if ( *p < 0x80 )
			p++;

		else if ( *p > 0xC1 && *p < 0xe0 && *(p+1) > 0x7f && *(p+1) < 0xC0)
			p += 2;

		else if ( *p == 0xe0 && *(p+1) > 0x9f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0)
			p += 3;

		else if ( *p > 0xe0  && *p < 0xf0 && *(p+1) > 0x7f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0)
			p += 3;

		else if ( *p == 0xf0 && *(p+1) > 0x8f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
			p += 4;

		else if ( *p > 0xf0 && *p < 0xf4 && *(p+1) > 0x7f && *(p+1) < 0xc0 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
			p += 4;

		else if ( *p == 0xf4 && *(p+1) > 0x7f && *(p+1) < 0x90 && *(p+2) > 0x7f && *(p+2) < 0xc0 && *(p+3) > 0x7f && *(p+3) < 0xc0 )
			p += 4;

		else
			return ((size_t) -1);

		len++;
	}

	return (len);
}
